Don't break a leg: Running birds from quail to ostrich prioritise leg safety and economy in uneven terrain

Cursorial ground birds are paragons of bipedal running that span a 500-fold mass range from quail to ostrich. Here we investigate the task-level control priorities of cursorial birds by analysing how they negotiate single-step obstacles that create a conflict between body stability (attenuating deviations in body motion) and consistent leg force–length dynamics (for economy and leg safety). We also test the hypothesis that control priorities shift between body stability and leg safety with increasing body size, reflecting use of active control to overcome size-related challenges. Weight-support demands lead to a shift towards straighter legs and stiffer steady gait with increasing body size, but it remains unknown whether non-steady locomotor priorities diverge with size. We found that all measured species used a consistent obstacle negotiation strategy, involving unsteady body dynamics to minimise fluctuations in leg posture and loading across multiple steps, not directly prioritising body stability. Peak leg forces remained remarkably consistent across obstacle terrain, within 0.35 body weights of level running for obstacle heights from 0.1 to 0.5 times leg length. All species used similar stance leg actuation patterns, involving asymmetric force–length trajectories and posture-dependent actuation to add or remove energy depending on landing conditions. We present a simple stance leg model that explains key features of avian bipedal locomotion, and suggests economy as a key priority on both level and uneven terrain. We suggest that running ground birds target the closely coupled priorities of economy and leg safety as the direct imperatives of control, with adequate stability achieved through appropriately tuned intrinsic dynamics

Don't break a leg: Running birds from quail to ostrich prioritise leg safety and economy in uneven terrain

Cursorial ground birds are paragons of bipedal running that span a 500-fold mass range from quail to ostrich. Here we investigate the task-level control priorities of cursorial birds by analysing how they negotiate single-step obstacles that create a conflict between body stability (attenuating deviations in body motion) and consistent leg force–length dynamics (for economy and leg safety). We also test the hypothesis that control priorities shift between body stability and leg safety with increasing body size, reflecting use of active control to overcome size-related challenges. Weight-support demands lead to a shift towards straighter legs and stiffer steady gait with increasing body size, but it remains unknown whether non-steady locomotor priorities diverge with size. We found that all measured species used a consistent obstacle negotiation strategy, involving unsteady body dynamics to minimise fluctuations in leg posture and loading across multiple steps, not directly prioritising body stability. Peak leg forces remained remarkably consistent across obstacle terrain, within 0.35 body weights of level running for obstacle heights from 0.1 to 0.5 times leg length. All species used similar stance leg actuation patterns, involving asymmetric force–length trajectories and posture-dependent actuation to add or remove energy depending on landing conditions. We present a simple stance leg model that explains key features of avian bipedal locomotion, and suggests economy as a key priority on both level and uneven terrain. We suggest that running ground birds target the closely coupled priorities of economy and leg safety as the direct imperatives of control, with adequate stability achieved through appropriately tuned intrinsic dynamics

Sociological approaches to the sexed running body and its construction through magazine and memory 1979-1995

This thesis explores the transforming embodiment of sex that is integral to the development of running/jogging culture between 1979-1995. Actor-network theory, a foucauldian approach and critical realism are each used to elucidate different aspects of running including the way it defines sex through the body, clothing, space and the rules and practices of running, jogging and racing

Efforts to Improve Short-Distance Running Achievement Through a Play Approach in Grade VIII Students

The purpose of this study was to determine the improvement of short-distance running achievement through a play approach to class VIII students. This type of research is classroom action research (CAR), with three cycles. The instrument used is a short distance running test. The subjects in this study were class VIII students, totaling 16 students. The data analysis technique used is descriptive statistics with percentages. Based on the results of the study, the results of the Short Distance Running test through a play approach to class VIII students obtained an average achievement in cycle 1 of 64.58, an average of 71.87 in cycle 2, and an average of cycle 3 obtained 80, From these results, it can be concluded that there is an increase in Short Distance Running Achievement through a Playing Approach for Class VIII Students. In this study, I created a student performance grid in which there are several indicators that will determine student scores. The KKM value for learning sprint distance running is obtained with several assessment criteria, namely mastery of movement techniques, enthusiasm and harmony in practicing sprint running, while for the aspects assessed, namely starting attitude, body posture when running, arm swing, body posture at the finish and grades. achievement (time).  To get a score above the KKM, in the learning process the teacher must be able to maximize the factors that support the achievement of the learning

Understanding the agility of running birds: Sensorimotor and mechanical factors in avian bipedal locomotion

Birds are a diverse and agile lineage of vertebrates that all use bipedal locomotion for at least part of their life. Thus birds provide a valuable opportunity to investigate how biomechanics and sensorimotor control are integrated for agile bipedal locomotion. This review summarizes recent work using terrain perturbations to reveal neuromechanical control strategies used by ground birds to achieve robust, stable and agile running. Early experiments in running guinea fowl aimed to reveal the immediate intrinsic mechanical response to an unexpected drop ('pothole') in terrain. When navigating the pothole, guinea fowl experience large changes in leg posture in the perturbed step, which correlates strongly with leg loading and perturbation recovery. Analysis of simple theoretical models of running has further confirmed the crucial role of swing-leg trajectory control for regulating foot contact timing and leg loading in uneven terrain. Coupling between body and leg dynamics results in an inherent trade-off in swing leg retraction rate for fall avoidance versus injury avoidance. Fast leg retraction minimizes injury risk, but slow leg retraction minimizes fall risk. Subsequent experiments have investigated how birds optimize their control strategies depending on the type of perturbation (pothole, step, obstacle), visibility of terrain, and with ample practice negotiating terrain features. Birds use several control strategies consistently across terrain contexts: 1) independent control of leg angular cycling and leg length actuation, which facilitates dynamic stability through simple control mechanisms, 2) feedforward regulation of leg cycling rate, which tunes foot-contact timing to maintain consistent leg loading in uneven terrain (minimizing fall and injury risks), 3) load-dependent muscle actuation, which rapidly adjusts stance push-off and stabilizes body mechanical energy, and 4) multi-step recovery strategies that allow body dynamics to transiently vary while tightly regulating leg loading to minimize risks of fall and injury. In future work, it will be interesting to investigate the learning and adaptation processes that allow animals to adjust neuromechanical control mechanisms over short and long timescales

Kinematic Basis for Body Specific Locomotor Mechanics and Perturbation Responses

Animals have evolved mechanical and neural strategies for locomotion in almost every environment, overcoming the complexities of their habitats using specializations in body structure and animal behavior. These specializations are created by neural networks responsible for generating and altering muscle activation. Species specific musculoskeletal anatomy and physiology determine how locomotion is controlled through the transformation of motor patterns into body movements. Furthermore, when these species specific locomotor systems encounter perturbations during running and walking their behavioral and mechanical attributes determine how stability is established during and after the perturbation. It is still not understood how species specific structural and behavioral variables contribute to locomotion in non-uniform environments. To understand how these locomotor properties produce unique gaits and stability strategies we compared three species of brachyuran crabs during normal and perturbed running. Although all crabs ran sideways, morphological and kinematic differences explained how each species produced its unique gait and stability response. Despite the differences in running behavior and perturbation response, animals tended to use locomotor resources that were in abundance during stabilizing responses. Each crab regained stability during the perturbation response by altering leg joint movements or harnessing the body\u27s momentum. These species body designs and running behavior show how slight changes in body structure and joint kinematics can produce locomotor systems with unique mechanical profiles and abilities. Understanding how evolutionary pressures have optimized animals\u27 locomotor ability to successfully move in different environments will provide a deeper understanding of how to mimic these movements through mathematical models and robotics

Narratives of and from a running-woman’s body: feminist phenomenological perspectives on running embodiment

The female sporting body has been studied in myriad ways over the past 25-30 years, including via a range of feminist frameworks (Hall 1996; Markula 2003; Hargreaves 2007). Despite this developing corpus, studies of sport only rarely engage in depth with the ‘flesh’ (Merleau-Ponty 1969) of the sweating, panting, pulsating, lived female sporting body (Allen-Collinson 2009) and a more corporeally-grounded, phenomenological perspective can enrich our understandings of women’s sporting ‘bodywork’. Here, I suggest that employing a sociological and feminist phenomenological framework can provide a powerful lens through which to explore narratives of the subjective, richly-textured, lived-body experiences of sport and physical activity. Phenomenology of course offers only one of a multiplicity of avenues to investigate sporting embodiment, and here I offer just a small glimpse of its possibilities. To date, sports studies utilising a phenomenological theoretical framework remain surprisingly under-developed, as Kerry and Armour (2000) highlighted over a decade ago, and which largely remains the case (Allen-Collinson 2009), including in relation to phenomenology’s fascinating off-shoot, ethnomethodology (Burke et al. 2008; Hockey and Allen-Collinson, 2013). Further, as Fisher (2000) notes, the significance of the interaction between phenomenology and feminism has only relatively recently begun to be explored. It seems timely, therefore, to address this intriguing, potentially productive, but sometimes uneasy nexus, focusing in this instance upon narratives of female running embodiment

Real-Time Online Re-Planning for Grasping Under Clutter and Uncertainty

We consider the problem of grasping in clutter. While there have been motion planners developed to address this problem in recent years, these planners are mostly tailored for open-loop execution. Open-loop execution in this domain, however, is likely to fail, since it is not possible to model the dynamics of the multi-body multi-contact physical system with enough accuracy, neither is it reasonable to expect robots to know the exact physical properties of objects, such as frictional, inertial, and geometrical. Therefore, we propose an online re-planning approach for grasping through clutter. The main challenge is the long planning times this domain requires, which makes fast re-planning and fluent execution difficult to realize. In order to address this, we propose an easily parallelizable stochastic trajectory optimization based algorithm that generates a sequence of optimal controls. We show that by running this optimizer only for a small number of iterations, it is possible to perform real time re-planning cycles to achieve reactive manipulation under clutter and uncertainty.Comment: Published as a conference paper in IEEE Humanoids 201

Why Run: A Website for New Runners

Running is one of the simplest forms of physical activity that a person can take part in, but can still seem daunting to someone who has never done it before. whyRun is a website that guides interested beginners, through a simple and easy user interface design, in the basics of the sport: Why they should get started, how to take those first steps, the different types of running, equipment needed, and how to stay safe and motivated. I believe that running can genuinely change not only how a person appears physically by getting a sedentary body into motion, but also helps individuals mentally by giving them an outlet for built up stress and a place to release negative energy. By creating a design identity and a means of access through website design, whyRun, will be targeted at beginners and will help share my love of running to a group of people who have started to believe that this is something they can take on, conquer, and enjoy

Running: anatomy of a middle-class obsession

This thesis explores recreational running as a social practice using the tools of Bourdeusian field analysis. Combining qualitative and quantitative methods, it maps and describes the social terrain of running, and explores the ways in which forms of running – and running per se – can be understood as symbolically potent performances of social position. The research methods include a large-scale survey of runners (n=2,637) and a series of in-depth interviews with runners (n=21). Running is also placed in its broader context as one of a wide range of forms of active leisure through a secondary analysis of data collected by Sport England. This study deploys Bourdieusian tools in a new way, using them to explode the ostensibly monolithic category of ‘running’ into its constituent parts, revealing a cosmos of socially distinctive (and even antagonistic) forms of running within it - a field of positions associated with distinctive cultural meanings and values. In mapping and analysing social and cultural differences within running, this study paints a new, more nuanced and complete picture of running culture as a dynamic, uneven and contested space through which social inequalities are reinforced and even justified. Key findings centre on the roles of class and gender in shaping running engagement through the mediation of access to capital and variations in habitus relating to tastes around the ‘healthy lifestyle’, body-shape and fitness ideals, ‘authenticity’ seeking, perceptions of competence, competition and ‘mental toughness’